Can Dogs and Cats Eat Onions?
By the VetVerdict team · Last updated October 18, 2026 · General information, not veterinary advice
Dogs
ToxicSeriousOnions (raw, cooked, or powdered) damage red blood cells and can cause anemia in dogs. Symptoms may take a few days to appear after ingestion.
Cats
ToxicSeriousCats are even more sensitive to onions than dogs, and even small, repeated amounts in food scraps can cause anemia over time.
What onions do to the body
Onions contain sulfur compounds that cause oxidative damage to red blood cells. The cells become fragile and break down, which can lead to a type of anemia. The same family of plants — chives, leeks, shallots and scallions — carries the same concern.
Cooked, powdered, or hidden in food
Cooking does not remove the problem: raw, cooked, fried and dehydrated onion all count, and onion powder is concentrated. It is easy to miss in broth, gravy, soup, pizza sauce, baby food and seasoning blends. Small amounts eaten repeatedly can add up over time.
Cats are more sensitive than dogs, and some dog breeds, including Akitas and Shiba Inus, are reported to be more susceptible.
Signs to watch for
- Weakness and lethargy
- Pale gums
- Rapid breathing or heart rate
- Reduced appetite
- Vomiting or diarrhea
- Reddish or dark urine
Signs are often delayed by a day or more, so the link to a meal can be easy to miss. If you know your pet ate something with onion, mention it to your vet even if your pet seems fine.
What to do
Call your veterinarian and describe what was eaten and how much. Treatment depends on timing and amount; it may involve making your pet vomit under supervision, supportive care, and blood tests, with oxygen or transfusion in severe cases.
Safer alternatives
If you are sharing human food, plain cooked chicken or green beans are safer choices — and check labels for "onion powder" or "garlic powder" before sharing any seasoned food.
Frequently asked questions
Is cooked onion safer than raw?
No. Cooking does not neutralize the compounds that harm red blood cells.
My dog licked a burger that had onions on it. Is that a problem?
A single lick is unlikely to matter, but larger amounts or repeated exposure can. If you are unsure how much was eaten, call your vet for advice.